<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        div {
            width: 100px;
            height: 100px;
            border-radius: 50%;
            background-color: salmon;
            background-image: linear-gradient(to right, transparent 50%, lightblue 0);
        }

        @keyframes spin {
            to {
                transform: rotate(.5turn);
            }
        }

        @keyframes bg {
            50% {
                background: salmon;
            }
        }

        div::before {
            content: '';
            display: block;
            margin-left: 50%;
            height: 100%;
            border-radius: 0 100% 100% 0 / 50%;
            background-color: inherit;
            transform-origin: left;
            animation: spin 50s linear infinite,
                bg 100s step-end infinite;
            animation-play-state: paused;
            animation-delay: inherit;
        }
    </style>
</head>

<body>
    <div class="pie" style="animation-delay: -20s"></div>
    <div class="pie" style="animation-delay: -60s"></div>
</body>

</html>